The present invention relates generally to tiller apparatus, and more particularly to a novel and improved rotary tiller adapted for tilling interstitial unplanted soil between plants or objects in a row.
Cultivating or tilling the interstitial unplanted soil between plants in a row to control weed growth, mulch, and aerate the soil is desirable for optimum plant growth and good husbandry. In the past, such tilling between plants in a row was accomplished by manual labor, such as the use of hoes. The cost of manual labor and the vastly increased sizes of crops and trees planted in rows in modern times as well as the desire for more convenience has rendered manual labor for such tasks obsolete.
Tilling the area between adjacent rows is easily accomplished mechanically with machines or cultivators mounted on tractors and the like. However, such conventional machines are usually not effective for tilling the soil between the plants in a row because the machines are too large and cumbersome to steer into and out of the typically limited space between the plants in a row without disturbing the plants. Consequently, a number of tiller machines have been devised for mounting on mobile vehicles such as tractors and adapted for moving into and out of the space between plants in a row in order to accommodate tilling the ground between the plants in a row while the tractor continues in a substantially straight course parallel to the row.
The following patents disclose examples of such devices which include some mechanism for moving tiller apparatus laterally in relation to the tractor into and out of the area between plants in a row: U.S. Pat. No. 2,489,633 issued to Fulgham; U.S. Pat. No. 2,664,802 issued to I. Myer; U.S. Pat. No. 2,718,836 issued to E. P. Pertics, et al; U.S. Pat. No. 2,764,077 issued E. P. Pertics, et al; U.S. Pat. No. 3,059,704 issued to Kasatkin; U.S. Pat. No. 3,117,632 issued to V. G. Caggiano, Jr.; U.S. Pat. No. 3,138,208 issuued to S. G. Simms; U.S. Pat. No. 3,190,364 issued to Maloney; U.S. Pat. No. 3,200,890 issued to Courtway, and U.S. Pat. No. 3,913,681 issued to W. D. Lincoln, et al. While all of these devices have enjoyed various degrees of success in effectively tilling the areas between plants in a row, there are still a number of drawbacks associated with them and problems that have not been solved heretofore. The prior art devices typically include cumbersome mechanical controls for extending and retracting a tiller into and out of the row. The U.S. Pat. No. 2,489,633 issued to Fulgham, U.S. Pat. No. 3,138,208 issued to Simms, and U.S. Pat. No. 3,200,390 issued to Courtway are examples of such devices that utilize various mechanical apparatus for extending and retracting a tiller into and out of a row. The Myer patent, U.S. Pat. No. 2,664,802 utilizes an electric solenoid mechanism for extending and retracting a tiller into and out of row. The U.S. Pat. No. 2,718,836 issued to Pertics et al, U.S. Pat. No. 2,764,077 issued to Pertics et al, U.S. Pat. No. 3,059,704 issued to Kasatkin, U.S. Pat. No. 3,913,681 issued to Lincoln et al all include hydraulic controls. The apparatus of the mechanically and electrically controlled tiller devices are cumbersome, and even the prior art hydraulically controlled tillers usually lack effective, sensitive, response and speed of travel in retracting and extending into the row.
While some of the prior art devices, such as those disclosed in U.S. Pat. No. 2,489,633 issued to Fulgham, U.S. Pat. No. 2,664,802 issued to Myer, U.S. Pat. No. 3,117,632 issued to Caggiano, U.S. Pat. No. 3,138,208 issued to Simms, U.S. Pat. No. 3,200,890 issued to Courtway, and U.S. Pat. No. 3,913,681 issued to Lincoln et al include sensing apparatus for sensing the plants and causing the tiller apparatus to move around the plants, such devices are lacking in specific desirable features such as accurate response to objects sensed, effective speed of response in retracting and extending a tiller out of and into the row, and sufficient manual control options to allow the operator flexibility in dealing with various sized weeds and other objects that might be encountered in the row in addition to the plants. For example, none of the prior art retractable tillers equipped with sensor apparatus include an effective combination of features to avoid destroying plants that are too small or weak to activate the sensors to retract the tiller from the row and to keep the tiller in the row to destroy weeds or other unwanted plants that are large enough to activate the sensors that cause the tillers to be retracted out of the row.
Another feature lacking in the prior art retractable tillers is effective depth control to keep the rotary tillers penetrating the soil at a desired depth while avoiding gouging deeply into the soil or lifting out of the soil as the tractor moves over uneven terrain in relation to the terrain of the soil between the plants being tilled. It should be noted in this regard that the rotary tillers disclosed in U.S. Pat. No. 3,117,632 issued to Caggiano, U.S. Pat. No. 3,190,364 issued to Maloney, and U.S. Pat. No. 3,200,890 issued to Courtway have dish-shaped rotors for riding the surface of the ground with short, rigid teeth extending downwardly therefrom. Such short rigid teeth apparatus, however, are ineffective in wet soil conditions where they ball up and in vine-type weeds where they wrap up.
In summary, while there have been a number of prior attempts to solve the problems of tilling soil between plants in a row, there is still a need for improved retractable tiller apparatus that is simple, accurate in sensing, swift in response, versatile in control options, and effective in maintaining optimum penetration depth control.